Search

To study the synergistic effects of water management and silicon (Si) foliar spraying on the uptake and transport of cadmium (Cd) in rice, we designed four treatments: conventional intermittent flooding + no Si foliar spraying (CK), continuous flooding throughout the growth stage + no Si foliar spraying (W), conventional intermittent flooding + Si foliar spraying (Si) and continuous flooding throughout the growth stage + Si foliar spraying (WSi). The results show that WSi treatment reduced the uptake and translocation of Cd by rice and significantly reduced the brown rice Cd content, with no effect on rice yield. Compared with CK, the Si treatment increased the net photosynthetic rate (Pn), stomatal conductance (Gs) and transpiration rate (Tr) of rice by 6.5–9.4%, 10.0–16.6% and 2.1–16.8%, respectively. The W treatment decreased these parameters by 20.5–27.9%, 8.6–26.8% and 13.3–23.3%, respectively, and the WSi treatment decreased them by 13.1–21.2%, 3.7–22.3% and 2.2–13.7%, respectively. The superoxide dismutase (SOD) and peroxidase (POD) activity decreased by 6.7–20.6% and 6.5–9.5%, respectively, following the W treatment. Following the Si treatment, SOD and POD activity increased by 10.2–41.1% and 9.3–25.1%, respectively, and following the WSi treatment, they increased by 6.5–18.1% and 2.6–22.4%, respectively. Si foliar spraying ameliorated the detrimental effects of continuous flooding throughout the growth stage on photosynthesis and antioxidant enzyme activity. We conclude that synergistic continuous flooding throughout the growth stage, combined with Si foliar spraying, can significantly block Cd uptake and translocation and is therefore an effective means of reducing the accumulation of Cd in brown rice.

The deep-sea aquaculture industry will become one of the important pillars of the future marine economy. However, the application of clean energy in the new scenario needs to be strengthened for platform operation. For this kind of renewable-energy distributed-generation system, an energy storage system is essential. A bidirectional DC–DC converter is essential for distributed power generation systems. It connects a variety of renewable energy sources with energy storage cells. A high-gain bidirectional Cuk circuit with zero ripple is proposed in the paper. It is characterized by a simple structure, zero ripple, low voltage stress of semiconductor power devices, and high voltage gain. A passivity-based control with linear active disturbance rejection is proposed to solve the problems of the large steady-state error. The zero steady-state error, strong robustness, and whole-range stability have been obtained for the proposed control strategy. Finally, a simulation was carried out. A 100 W, 48 V/400 V prototype was built to verify the validity of the theoretical analysis for the proposed circuit. The improved passivity-based control strategy was verified to solve the contradiction between rapidity and overshoot. It can be realized to improve the dynamic performance of the proposed converter and achieve robust control.

The spatiotemporal heterogeneity of rice canopy leaves at different leaf positions is very important for non-destructive monitoring under Cadmium (Cd) stress, and is one of the key problems that need to be solved urgently in modern agriculture. This study aims to explore the temporal and spatial heterogeneity of chlorophyll content and fluorescence in rice canopy leaves under different Cd stress concentrations. The responses of the relative chlorophyll content (SPAD) and Chlorophyll fluorescence (ChlF) parameters to Cd stress in the tillering, heading, and filling stages were analyzed through pot experiments with three Cd concentrations: 0.20 mg·kg−1 (CK), 0.60 mg·kg−1 (Cd1), and 1.60 mg·kg−1 (Cd2). Results showed that the canopy leaf SPAD value increased with increasing Cd concentration. Compared with CK, the leaf SPAD value in the Cd1 and Cd2 treatments were 1.91–3.45% and 5.52–12.01% lower, respectively. The SPAD value of the lower leaves was higher in the tillering stage, while the SPAD value of the upper leaves was higher in the heading and filling stages. The non-photochemical quenching coefficient (NPQ) of the third leaf (D3), the initial fluorescence yield (Fo) of the second leaf (D2), and the maximum photochemical efficiency (Fv/Fm) of photosystem II (PSII) in the tillering stage; the NPQ, Fo, and Fv/Fm of the D3 in the heading stage; and the NPQ, Fo, Fv/Fm, and Fv/Fm of the D2 in the filling stage were more sensitive to Cd stress than the other leaves and ChlF parameters.

Background: The recent experimental discovery of drip-line nucleus 39Na has attracted great interest in theoretical studies of exotic nuclear structures in this mass region. Methods: We solve the Skyrme–Hartree–Fock–Bogoliubov (Skyrme-HFB) equation within deformed coordinate-spaces. The present approach is suitable for descriptions of weakly bound deformed nuclei with continuum effects and deformed halo structures. Results: The systematical two-neutron separation energies are obtained with the SkMext1* and UNEDF0ext1 forces for Na and Mg isotopes close to the neutron drip line. The density distributions show that 39Na and 42Mg have deformed halo structures. Furthermore, there are significant influences of various pairing interactions on halo shapes at large distances. Conclusions: Both 39Na and 42Mg are very weakly bound with well prolate deformed cores. However, their surface halo structures are dependent on the choices of pairing interactions. The volume-type pairing interaction tends to predict a prolate deformed halo, while the halo deformations at large distances are reduced by adopting the surface pairing. We demonstrate that 39Na and 42Mg are promising candidates for two-neutron deformed halo nuclei.

Based on MS and NMR data and bioassay-guided tracing, three insecticidal alkaloids I, II and III from Cynanchum mongolicum were identified to be antofine N-oxide, antofine and tylophorine. Alkaloid I was more toxic than alkaloids II and III, but they were less active against Spodoptera litura than total alkaloids. The contact toxicity from these alkaloids against the aphid Lipaphis erysimi was significant, as the 24 h-LC50 values of alkaloids I, II, III and total alkaloids were 292.48, 367.21, 487.791 and 163.52 mg/L, respectively. The development disruption of S. litura larvae was tested, the pupation and emergence rates of S. litura decreased and the acute mortality of S. litura increased significantly by day 3 after being injected in their body cavity with 10–40 mg/L of total alkaloid. The ecdysone titer of treated S. litura larvae and prepupae declined with increasing alkaloid concentration. The alkaloids of Cynanchum mongolicum are potential insect growth inhibitors.